Screw head

ABSTRACT

A screw head having a V shaped kerf whose intersecting legs are off-center to provide a reliable coupling with a similarly flanged screw driver.

United States Patent Roehrig May 7, 1974 [54] SCREW HEAD FOREIGN PATENTS OR APPLICATIONS [761 Inventor! Roehl'ig 125 Andrews, 59,739 5/1942 Denmark I.'. 85/45 MCKPBSPOH, Pa, 15135 186,146 6/1907 Germany 85/45 [22] Filed: Apr. 19, 1972 [21] Appl No: 245,404 Primary Examiner-Edward C. Allen [52] U.S. Cl. 85/45, l45/5O A 57 ABSTRACT [51] Int. Cl. Fl6b 23/00 [58] Field of Search 85/45; 145/50 A A screw head having a V shaped kerf whose intersecting legs are off-center to provide a reliable coupling [56] References Cited with a similarly flanged screw driver.

UNITED STATES PATENTS 2 Cl 5 D 379,200 3/1888 Hanlon 85/45 aims rawmg lgures SCREW HEAD This invention relates generally to a screw head and, more particularly, to the kerf construction thereof and to a correspondingly shaped screw driver for turning the head.

Conventionally used kerfs on screw heads comprise either a single slot across the diameter of the screw head or a Phillips head which is a four pronged tapered indenture on a screw head.

An outstanding disadvantage of the straight slot is that unless the screw driver bit snugly flts the width of the slot, the bit will contact the slot at only two points on the extreme ends of the bit. Such minute points of contact generally cause the bit to jump out of the slot if substantial pressure is exerted, or to slide off the open ends of the slot.

A disadvantage of the Phillips head is that the four pronged indenture is tapered from the top surface of the screw head into the screw itself and the screw driver bit is tapered in a like manner, which tapered edges tend to back out of the screw driver bit when substantial pressure is applied.

Less popular cruciform kerfs having an angle of 90 between kerfs enables only short lengths of the kerf and the cruciform shape involves more difficulty in machinmg.

An object of the present invention is to provide a novel screw head kerf which is devoid of the disadvantages of the above mentioned conventionally used kerfs and which kerf arrangement assures a strong hold between the screw driver and screw head when turning the screw, also which kerf arrangement is inexpensive to manufacture.

A more specific object of the present invention is to provide a somewhat V-shaped kerf on a screw head wherein the intersecting legs of the V intersect offcenter of the head to provide a secure grip betweenthe screw driver and head.

. Other objects and advantages will become more apparent from a study of the following description, taken with the accompanying drawing wherein:

FIG. 1 is a perspective view of a wood screw having a head provided with a kerf according to the teachings of the present invention;

FIG. 2 is a top view, somewhat enlarged, of the screw head shown in FIG. 1;

FIG. 3 is a view similar to FIG. 2 showing a modification of the kerf;

FIG. 4 is another view similar to FIG. 2 with a slightly different arrangement of kerf; and,

FIG. 5 is a perspective view of a screw driver for use in driving the screws shown in FIGS. 1 to 4 inclusive.

about one-eighth inch or more in depth. The angle be- 6 tween kerfs 3, 3 is in excess of 90 and less than 180 and preferably in the range of about 120 to 160 and more ideally in the neighborhood of 140.

FIG. 3 shows a somewhat modified head 4 in which the kerf grooves 5, 5 intersect at 6 along the circumference of the head.

FIG. 4 shows a further modification of the head 7 wherein the kerf grooves 8, 8 intersect near the perimeter of the screw head.

FIG. 5 shows, generally, a screw driver 9 comprising a handle 10 and a driver portion 11 of steel or other suitable material in the form of an angle comprising flanges 12, 12 having the same angle therebetween as the kerfs on the head of the screw to be driven thereby. Thus the flange is preferably of an angle between and 160 and more preferably of the order of An outstanding advantage of the present invention is that the same screw driver, shown in FIG. 5, may be used on widely varying sizes of screws, even though the kerfs of the screws are longer or shorter than the driving flanges, l2, 12 since the only requirement is that the angle of the kerfs correspond to the angles of the flanges l2, 12 of the screw driver. This enables a single screw driver to fit numerous sizes of screws and still maintain a rigid anchor therewith.

Another advantage of the present construction is that the kerfs may be made on the head simply by two passes of a drilling machine.

Still another advantage is that kerfs of maximum length compared to the diameter size of the head are provided so as to provide the greatest total length of kerf grooves of V shape, as compared to the situation wherein the intersection of the V might be at the center of the screw head. Considerable advantages are obtained by off-setting the intersection of the V shaped kerf from the center of the head. For example, if an automatic screw driver is used, the center of gravity of the flanges will be substantially at the center of the screw head and thus prevent vibration from dynamic unbalance of the rotating driver.

Thus it will be seen that l have provided a novel kerf shape for a screw head which provides more efficient and assured connection with a correspondingly shaped screw driver and which enables a single size of screw driver to fit numerous sizes of screw heads; furthermore, I have provided a somewhat V shaped kerf whose intersection is off-center of the screw head to provide maximum length of the sides or wings of the V groove for a given diameter head so as to provide a considerably stronger hold with a correspondingly angled screw driver. I

While I have illustrated and described several embodiments of my invention, it will be understood that these are by way of illustration only and that various changes and modifications may be contemplated within the invention and following claims.

I claim:

1. A screw head having a V shaped kerf wherein intersecting straight and continuous grooves forming the legs of the V intersect at a point which is off-set from the center of the screw head, said point of intersection and the extremities of the legs of the V-shaped kerf extending to the perimeter of the screw head.

2. A screw head having a V shaped kerf wherein intersecting straight and continuous grooves forming the legs of the V intersect at a point which is off-set from the center of the screw head, and wherein the angle of 5 the legs of said kerf is in the range of between about 

1. A screw head having a V shaped kerf wherein intersecting straight and continuous grooves forming the legs of the V intersect at a point which is off-set from the center of the screw head, said point of intersection and the extremities of the legs of the V-shaped kerf extending to the perimeter of the screw head.
 2. A screw head having a V shaped kerf wherein intersecting straight and continuous grooves forming the legs of the V intersect at a point which is off-set from the center of the screw head, and wherein the angle of the legs of said kerf is in the range of between about 120* to 160*. 